Platelets interact with soluble and insoluble collagens through characteristically different reactions
Platelets interact with soluble and insoluble collagens through characteristically different reactions
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DOI：
10.1074/jbc.273.24.14827
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发表时间：
1998-06-12
影响因子：
4.8
通讯作者：
Moroi, M
中科院分区：
文献类型：
--
作者：
Jung, SM;Moroi, M
血小板与可溶性和不溶性胶原蛋白的相互作用，其特征在于通过结合研究。与静息血小板相反，细胞与活化剂TS 2/16（整合素α（2）β（1）活化抗体）、凝血酶、胶原相关肽或ADP反应，表现出Mg 2+依赖性的特异性可溶性胶原结合，但受前列腺素I-2、Ca 2+和Gi 9（抗整合素α（2）β（1）抗体）抑制。每个血小板有1500-3500个可溶性胶原结合位点，解离常数为3.5-9 × 10（-8）M。这是第一个研究表明可溶性胶原蛋白与血小板的特异性结合;我们的数据强烈表明，受体是整合素α（2）β（1），它在血小板活化后被激活。这些结果表明，血小板的活化将整合素α（2）β（1）转化为对可溶性胶原具有更高亲和力结合位点的状态。将可溶性胶原-血小板相互作用与血小板与纤维状胶原的相互作用进行比较，纤维状胶原迄今尚未被证明特异性结合血小板。在这里，我们证明了特异性的双相纤维胶原结合。一个相是快速的和不依赖于金属离子的，并且占大部分结合。另一个阶段是缓慢的和Mg 2+依赖的。可溶性和纤维性胶原蛋白的特异性结合的特征差异表明两种不同的胶原蛋白受体的不同贡献。
Platelet interaction with soluble and insoluble collagens was characterized through binding studies. In contrast to resting platelets, cells reacted with activators, TS2/16 (integrin alpha(2) beta(1)-activating antibody), thrombin, collagen-related peptide, or ADP, exhibited specific soluble collagen binding that is Mg2+-dependent, but inhibited by prostaglandin I-2, Ca2+, and Gi9 (anti-integrin alpha(2) beta(1) antibody). Each platelet has 1500-3500 soluble collagen binding sites, with a dissociation constant of 3.5-9 x 10(-8) M. This is the first study to show the specific binding of soluble collagen to platelets; our data strongly suggest that the receptor is integrin alpha(2) beta(1) after it becomes activated upon platelet activation. These results suggest that activation of platelets transforms integrin alpha(2) beta(1) to a state with higher affinity binding sites for soluble collagen. The soluble collagen-platelet interaction was compared with the platelet interaction with fibrillar collagen, which has until now not been demonstrated to bind specifically to platelets. Here, we demonstrated specific, biphasic fibrillar collagen binding. One phase is rapid and metal ion-independent, and accounts for most of the binding. The other phase is slow and Mg2+-dependent. The characteristic differences in the specific bindings of soluble and fibrous collagens demonstrate the different contributions of two different collagen receptors.